DBS uses high-frequency electrical stimulation targeted to
the specific areas of the brain involved in neuropsychiatric disease.
During the study, twenty patients were treated with DBS for
12 months. The team found that twelve of 20 patients experienced a significant
decrease in depressive symptoms by six months with seven patients essentially
well with few remaining symptoms
Benefits were largely maintained at 12 months with continued
stimulation. No long-term side effects were reported.
Each patient was implanted with two thin wire electrodes
(one on each side of the brain) in the white matter adjacent to subcallosal
cingulate region or SCG.
The other end of each wire was connected under the skin of
the neck to a pulse generator implanted in the chest -- similar to a pacemaker
-- that directs the electrical current.
The researchers regulated the intensity of the current
according to the response of the patient.
"In previous studies using brain imaging, we found the
subcallosal cingulate region was a key region in an emerging emotion regulation
circuit implicated in major depression," said Helen S. Mayberg, MD, lead
researcher from University of Toronto.
"We postulated that if stimulation worked for the
treatment of other neurological disorders where abnormal function of specific
circuits was well established, such as Parkinson''s disease, then stimulation
of the Cg25 region within this apparent depression circuit might provide
significant benefit for patients with treatment-resistant depression," she
The team included researchers from University of Toronto and
Emory University School of Medicine.
The study is reported in the online issue of Biological